1. Field of the Invention
The present invention is directed to a wet clutch arrangement, particularly a starting clutch for a vehicle, comprising a housing arrangement filled or finable with fluid, a friction coupling region having a first friction surface formation rotating with the housing arrangement around an axis of rotation, and a second friction surface formation that rotates with a driven element around the axis of rotation and that can be brought into frictional engagement with the first friction surface formation, a fluid coupling region with an impeller rotating with the housing arrangement around the axis of rotation and with a turbine that rotates with the driven element around the axis of rotation and which, along with the impeller, defines a toroidal fluid circulation space.
In wet clutch arrangements, a fundamental problem is that after an extended period of disuse the fluid contained in the housing arrangement during driving operation has partially flowed out of the housing arrangement into a fluid sump in a gearbox. This means that the housing arrangement is only partially filled with fluid, generally oil, for subsequent starting, and the fluid still contained in the housing arrangement collects in the radially outer region as a result of centrifugal force during rotation of the housing arrangement. However, in view of the fact that fluid is generally required to engage the friction coupling region, there may occur a state in which no torque can be transmitted over a certain period of time after starting for lack of the possibility of filling the piston chamber and, therefore, engaging the friction coupling region.